The synthesis of (-)-depentylperhydrohistrionicotoxin (I, R = H) from the 2-cyano-6-oxazolopiperidine synthon (-)-II was achieved. The spiro skeleton was formed by an aldol cyclization of a Me ketone and an aldehyde function belonging to chains borne at C-2. Since the transformation of (+-)-I (R = H) into (+-)-perhydrohistrionicotoxin (I, R = pentyl) is known, the synthesis of (-)-I (R = H) represents a formal synthesis of (-)-perhydrohistrionicotoxin. [on SciFinder (R)]